Fighter aircraft

U.S. Air Force fighter aircraft representing different eras; a World War II P-38 Lightning (upper-right), a pair of F-86 Sabres from the early jet age and a modern F-22 Raptor (lower-left)

A fighter aircraft is a military aircraft designed primarily for air-to-air combat against other aircraft,[1] as opposed to bombers and attack aircraft, whose main mission is to attack ground targets. The hallmarks of a fighter are its speed, maneuverability, and small size relative to other combat aircraft.

Many fighters have secondary ground-attack capabilities, and some are designed as dual-purpose fighter-bombers; often aircraft that do not fulfill the standard definition are called fighters. This may be for political or national security reasons, for advertising purposes, or other reasons.[2]

A fighter's main purpose is to establish air superiority over a battlefield. Since World War I, achieving and maintaining air superiority has been considered essential for victory in conventional warfare.[3] The success or failure of a belligerent's efforts to gain air superiority hinges on several factors including the skill of its pilots, the tactical soundness of its doctrine for deploying its fighters, and the numbers and performance of those fighters. Because of the importance of air superiority, since the early days of aerial combat armed forces have constantly competed to develop technologically superior fighters and to deploy these fighters in greater numbers, and fielding a viable fighter fleet consumes a substantial proportion of the defense budgets of modern armed forces.[4]

The word "fighter" did not become the official English-language term for such aircraft until after World War I. In the British Royal Flying Corps and Royal Air Force these aircraft were referred to as "scouts" into the early 1920s. The U.S. Army called their fighters "pursuit" aircraft from 1916 until the late 1940s. In most languages a fighter aircraft is known as a hunter, or hunting aircraft (avion de chasse, Jagdflugzeuge, avión de caza etc.). Exceptions include Russian, where a fighter is an "истребитель" (pronounced "istrebitel"), meaning "exterminator", and Hebrew where it is "matose krav" (literally "battle plane").

As a part of military nomenclature, a letter is often assigned to various types of aircraft to indicate their use, along with a number to indicate the specific aircraft. The letters used to designate a fighter differ in various countries – in the English-speaking world, "F" is now used to indicate a fighter (e.g. Lockheed Martin F-35 Lightning II or Supermarine Spitfire F.22), though when the pursuit designation was used in the US, they were "P" types (e.g. Curtiss P-40 Warhawk). In Russia "I" was used (Polikarpov I-16), while the French continue to use "C" (Nieuport 17 C.1).

Although the term "fighter" specifies aircraft designed to shoot down other aircraft, such designs are often also useful as multirole fighter-bombers, strike fighters, and sometimes lighter, fighter-sized tactical ground-attack aircraft. This has always been the case, for instance the Sopwith Camel and other "fighting scouts" of World War I performed a great deal of ground-attack work. In World War II, the USAAF and RAF often favored fighters over dedicated light bombers or dive bombers, and types such as the Republic P-47 Thunderbolt and Hawker Hurricane that were no longer competitive as aerial combat fighters were relegated to ground attack. Several aircraft, such as the F-111 and F-117, have received fighter designations though they had no fighter capability due to political or other reasons. The F-111B variant was originally intended for a fighter role with the U.S. Navy, but it was cancelled. This blurring follows the use of fighters from their earliest days for "attack" or "strike" operations against ground targets by means of strafing or dropping small bombs and incendiaries. Versatile multirole fighter-bombers such as the McDonnell Douglas F/A-18 Hornet are a less expensive option than having a range of specialized aircraft types.

Fighters were developed in World War I to deny enemy aircraft and dirigibles the ability to gather information by reconnaissance over the battlefield. Early fighters were very small and lightly armed by later standards, and most were biplanes built with a wooden frame covered with fabric, and a maximum airspeed of about 100 mph (160 km/h). As control of the airspace over armies became increasingly important, all of the major powers developed fighters to support their military operations. Between the wars, wood was largely replaced in part or whole by metal tubing, and finally aluminium stressed skin structures (monocoque) began to predominate.

On 15 August 1914, Miodrag Tomić encountered an enemy plane while conducting a reconnaissance flight over Austria-Hungary. The Austro-Hungarian aviator initially waved at Tomić, who waved back. The enemy pilot then took a revolver and began shooting at Tomić's plane.[6] Tomić produced a pistol of his own and fired back.[7] He swerved away from the Austro-Hungarian plane and the two aircraft eventually parted ways. [8] It was considered the first exchange of fire between aircraft in history.[9] Within weeks, all Serbian and Austro-Hungarian aircraft were armed.[6] The Serbians equipped their planes with 8-millimetre (0.31 in) Schwarzlose MG M.07/12 machine guns, six 100-round boxes of ammunition and several bombs.[10]

By World War II, most fighters were all-metal monoplanes armed with batteries of machine guns or cannons and some were capable of speeds approaching 400 mph (640 km/h). Most fighters up to this point had one engine, but a number of twin-engine fighters were built; however they were found to be outmatched against single-engine fighters and were relegated to other tasks, such as night fighters equipped with primitive radar sets.

By the end of the war, turbojet engines were replacing piston engines as the means of propulsion, further increasing aircraft speed. Since the weight of the turbojet engine was far less than piston engine, having two engines was no longer a handicap and one or two were used, depending on requirements. This in turn required the development of ejection seats so the pilot could escape, and G-suits to counter the much greater forces being applied to the pilot during maneuvers.

In the 1950s, radar was fitted to day fighters, since due to ever increasing air-to-air weapon ranges, pilots could no longer see far enough ahead to prepare for the opposition. Subsequently, radar capabilities grew enormously and are now the primary method of target acquisition. Wings were made thinner and swept back to reduce transonic drag, which required new manufacturing methods to obtain sufficient strength. Skins were no longer sheet metal riveted to a structure, but milled from large slabs of alloy. The sound barrier was broken, and after a few false starts due to required changes in controls, speeds quickly reached Mach 2, past which aircraft cannot maneuver sufficiently to avoid attack.

Air-to-air missiles largely replaced guns and rockets in the early 1960s since both were believed unusable at the speeds being attained, however the Vietnam War showed that guns still had a role to play, and most fighters built since then are fitted with cannon (typically between 20 and 30 mm in caliber) in addition to missiles. Most modern combat aircraft can carry at least a pair of air-to-air missiles.

In the 1970s, turbofans replaced turbojets, improving fuel economy enough that the last piston engined support aircraft could be replaced with jets, making multi-role combat aircraft possible. Honeycomb structures began to replace milled structures, and the first composite components began to appear on components subjected to little stress.

With the steady improvements in computers, defensive systems have become increasingly efficient. To counter this, stealth technologies have been pursued by the United States, Russia, India and China. The first step was to find ways to reduce the aircraft's reflectivity to radar waves by burying the engines, eliminating sharp corners and diverting any reflections away from the radar sets of opposing forces. Various materials were found to absorb the energy from radar waves, and were incorporated into special finishes that have since found widespread application. Composite structures have become widespread, including major structural components, and have helped to counterbalance the steady increases in aircraft weight—most modern fighters are larger and heavier than World War II medium bombers.

The word "fighter" was first used to describe a two-seater aircraft with sufficient lift to carry a machine gun and its operator as well as the pilot. Some of the first such "fighters" belonged to the "gunbus" series of experimental gun carriers of the British Vickers company that culminated in the Vickers F.B.5 Gunbus of 1914. The main drawback of this type of aircraft was its lack of speed. Planners quickly realized that an aircraft intended to destroy its kind in the air had to be fast enough to catch its quarry.

Another type of military aircraft was to form the basis for an effective "fighter" in the modern sense of the word. It was based on the small fast aircraft developed before the war for such air races as the Gordon Bennett Cup and Schneider Trophy. The military scout airplane was not expected to carry serious armament, but rather to rely on its speed to reach the scout or reconnoiter location and return quickly to report – essentially an aerial horse. British scout aircraft, in this sense, included the Sopwith Tabloid and Bristol Scout. French equivalents included the Morane-Saulnier N.

Soon after the commencement of the war, pilots armed themselves with pistols, carbines, grenades, and an assortment of improvised weapons. Many of these proved ineffective as the pilot had to fly his airplane while attempting to aim a handheld weapon and make a difficult deflection shot. The first step in finding a real solution was to mount the weapon on the aircraft, but the propeller remained a problem since the best direction to shoot is straight ahead. Numerous solutions were tried. A second crew member behind the pilot could aim and fire a swivel-mounted machine gun at enemy airplanes; however, this limited the area of coverage chiefly to the rear hemisphere, and effective coordination of the pilot's maneuvering with the gunner's aiming was difficult. This option was chiefly employed as a defensive measure on two-seater reconnaissance aircraft from 1915 on. Both the SPAD S.A and the Royal Aircraft Factory B.E.9 added a second crewman ahead of the engine in a pod but this was both hazardous to the second crewman and limited performance. The Sopwith L.R.T.Tr. similarly added a pod on the top wing with no better luck.

Billy Bishop sitting in his Nieuport 23 with the machine gun (just visible at the top of the picture) mounted to fire over the propeller.

An alternative was to build a "pusher" scout such as the Airco DH.2, with the propeller mounted behind the pilot. The main drawback was that the high drag of a pusher type's tail structure made it slower than a similar "tractor" aircraft.

A better solution for a single seat scout was to mount the machine gun (rifles and pistols having been dispensed with) to fire forwards but outside the propeller arc. Wing guns were tried but the unreliable weapons available required frequent clearing of jammed rounds and misfires and remained impractical until after the war. Mounting the machine gun over the top wing worked well and was used long after the ideal solution was found. The Nieuport 11 of 1916 and Royal Aircraft Factory S.E.5 of 1918 both used this system with considerable success; however, this placement made aiming difficult and the location made it difficult for a pilot to both maneuver and have access to the gun's breech. The British Foster mounting was specifically designed for this kind of application, fitted with the Lewis Machine gun, which due to its design was unsuitable for synchronizing.

The actual aircraft used by Wintgens in his pioneering aerial engagement, his Fokker M.5K/MG with IdFlieg military serial number "E.5/15", as it appeared at the time of the engagement.

The need to arm a tractor scout with a forward-firing gun whose bullets passed through the propeller arc was evident even before the outbreak of war and inventors in both France and Germany devised mechanisms that could time the firing of the individual rounds to avoid hitting the propeller blades. Franz Schneider, a Swiss engineer, had patented such a device in Germany in 1913, but his original work was not followed up. French aircraft designer Raymond Saulnier patented a practical device in April 1914, but trials were unsuccessful because of the propensity of the machine gun employed to hang fire due to unreliable ammunition.

In December 1914, French aviator Roland Garros asked Saulnier to install his synchronization gear on Garros' Morane-Saulnier Type L. Unfortunately the gas-operated Hotchkiss machine gun he was provided had an erratic rate of fire and it was impossible to synchronize it with a spinning propeller. As an interim measure, the propeller blades were armored and fitted with metal wedges to protect the pilot from ricochets. Garros' modified monoplane was first flown in March 1915 and he began combat operations soon thereafter. Garros scored three victories in three weeks before he himself was downed on 18 April and his airplane, along with its synchronization gear and propeller was captured by the Germans.

Meanwhile, the synchronization gear (called the Stangensteuerung in German, for "pushrod control system") devised by the engineers of Anthony Fokker's firm was the first system to see production contracts, and would make the Fokker Eindecker monoplane a feared name over the Western Front, despite its being an adaptation of an obsolete pre-war French Morane-Saulnier racing airplane, with a mediocre performance and poor flight characteristics. The first victory for the Eindecker came on 1 July 1915, when LeutnantKurt Wintgens, flying with the Feldflieger Abteilung 6 unit on the Western Front, forced down a Morane-Saulnier Type L two-seat "parasol" monoplane just east of Luneville. Wintgens' aircraft, one of the five Fokker M.5K/MG production prototype examples of the Eindecker, was armed with a synchronized, air-cooled aviation version of the Parabellum MG14 machine gun.

The success of the Eindecker kicked off a competitive cycle of improvement among the combatants, both sides striving to build ever more capable single-seat fighters. The Albatros D.I and Sopwith Pup of 1916 set the classic pattern followed by fighters for about twenty years. Most were biplanes and only rarely monoplanes or triplanes. The strong box structure of the biplane provided a rigid wing that allowed the accurate lateral control essential for dogfighting. They had a single operator, who flew the aircraft and also controlled its armament. They were armed with one or two Maxim or Vickers machine guns, which were easier to synchronize than other types, firing through the propeller arc. Gun breeches were directly in front of the pilot, with obvious implications in case of accidents, but jams could be cleared in flight, while aiming was simplified.

The use of metal aircraft structures was pioneered before World War I by Breguet but would find its biggest proponent in Anthony Fokker, who used chrome-molybdenum steel tubing for the fuselage structure of all his fighter designs, while the innovative German engineer Hugo Junkers developed two all-metal, single-seat fighter monoplane designs with cantilever wings: the strictly experimental Junkers J 2 private-venture aircraft, made with steel, and some forty examples of the Junkers D.I, made with corrugated duralumin, all based on his experience in creating the pioneering Junkers J 1 all-metal airframe technology demonstration aircraft of late 1915. While Fokker would pursue steel tube fuselages with wooden wings until the late 1930s, and Junkers would focus on corrugated sheet metal, Dornier was the first to build a fighter (The Dornier-Zeppelin D.I) made with pre-stressed sheet aluminium and having cantelevered wings, a form that would replace all others in the 1930s.

As collective combat experience grew, the more successful pilots such as Oswald Boelcke, Max Immelmann, and Edward Mannock developed innovative tactical formations and maneuvers to enhance their air units' combat effectiveness.

Allied and – before 1918 – German pilots of World War I were not equipped with parachutes, so in-flight fires or structural failure were often fatal. Parachutes were well-developed by 1918 having previously been used by balloonists, and were adopted by the German flying services during the course of that year. The well known and feared Manfred von Richthofen "Red Baron" was wearing one when he was killed, but the allied command continued to oppose their use on various grounds.[11]

In April 1917, during a brief period of German aerial supremacy a British pilot's average life expectancy was 93 flying hours, or about three weeks of active service.[12][13] More than 50,000 airmen from both sides died during the war.[14]

Fighter development stagnated between the wars, especially in the United States and the United Kingdom, where budgets were small. In France, Italy and Russia, where large budgets continued to allow major development, both monoplanes and all metal structures were common. By the end of the 1920s, however, those countries overspent themselves and were overtaken in the 1930s by those powers that hadn't been spending heavily, namely the British, the Americans and the Germans.

Given limited defense budgets, air forces tended to be conservative in their aircraft purchases, and biplanes remained popular with pilots because of their agility, and remained in service long after they had ceased to be competitive. Designs such as the Gloster Gladiator, Fiat CR.42, and Polikarpov I-15 were common even in the late 1930s, and many were still in service as late as 1942. Up until the mid-1930s, the majority of fighters in the US, the UK, Italy and Russia remained fabric-covered biplanes.

Fighter armament eventually began to be mounted inside the wings, outside the arc of the propeller, though most designs retained two synchronized machine guns directly ahead of the pilot, where they were more accurate (that being the strongest part of the structure, reducing the vibration to which the guns were subjected to). Shooting with this traditional arrangement was also easier for the further reason that the guns shot directly ahead in the direction of the aircraft's flight, up to the limit of the guns range; unlike wing-mounted guns which to be effective required to be harmonised, that is, preset to shoot at an angle by ground crews so that their bullets would converge on a target area a set distance ahead of the fighter. Rifle-caliber .30 and .303 in (7.62 mm) caliber guns remained the norm, with larger weapons either being too heavy and cumbersome or deemed unnecessary against such lightly built aircraft. It was not considered unreasonable to use World War I-style armament to counter enemy fighters as there was insufficient air-to-air combat during most of the period to disprove this notion.

The rotary engine, popular during World War I, quickly disappeared, its development having reached the point where rotational forces prevented more fuel and air from being delivered to the cylinders, which limited horsepower. They were replaced chiefly by the stationary radial engine though major advances led to inline engines, which gained ground with several exceptional engines—including the 1,145 cu in (18.76 l) V-12 Curtiss D-12. Aircraft engines increased in power several-fold over the period, going from a typical 180 hp (130 kW) in the 900-kg Fokker D.VII of 1918 to 900 hp (670 kW) in the 2,500-kg Curtiss P-36 of 1936. The debate between the sleek in-line engines versus the more reliable radial models continued, with naval air forces preferring the radial engines, and land-based forces often choosing in-line units. Radial designs did not require a separate (and vulnerable) cooling system, but had increased drag. In-line engines often had a better power-to-weight ratio, but there were radial engines that kept working even after having suffered significant battle damage.

Some air forces experimented with "heavy fighters" (called "destroyers" by the Germans). These were larger, usually twin-engined aircraft, sometimes adaptations of light or medium bomber types. Such designs typically had greater internal fuel capacity (thus longer range) and heavier armament than their single-engine counterparts. In combat, they proved vulnerable to more agile single-engine fighters.

The primary driver of fighter innovation, right up to the period of rapid re-armament in the late 1930s, were not military budgets, but civilian aircraft racing. Aircraft designed for these races introduced innovations like streamlining and more powerful engines that would find their way into the fighters of World War II. The most significant of these was the Schneider Trophy races, where competition grew so fierce, only national governments could afford to enter.

Parasol monoplanes were popular in many European countries, and paved the way for cantilever low-wing monoplanes. This is a restored Swiss Air Force Dewoitine D.26

At the very end of the inter-war period in Europe came the Spanish Civil War. This was just the opportunity the German Luftwaffe, Italian Regia Aeronautica, and the Soviet Union's Red Air Force needed to test their latest aircraft. Each party sent numerous aircraft types to support their sides in the conflict. In the dogfights over Spain, the latest Messerschmitt Bf 109 fighters did well, as did the Soviet Polikarpov I-16. The German design had considerably more room for development however and the lessons learned led to greatly improved models in World War II. The Russians, whose side lost, failed to keep up and despite newer models coming into service, I-16s were outfought by the improved Bf 109s in World War II, while remaining the most common Soviet front-line fighter into 1942. For their part, the Italians developed several monoplanes such as the Fiat G.50, but being short on funds, were forced to continue operating obsolete Fiat CR.42 biplanes.

From the early 1930s the Japanese had been at war against both the Chinese Nationalists and the Russians in China, and used the experience to improve both training and aircraft, replacing biplanes with modern cantilever monoplanes and creating a cadre of exceptional pilots for use in the Pacific War. In the United Kingdom, at the behest of Neville Chamberlain, (more famous for his 'peace in our time' speech) the entire British aviation industry was retooled, allowing it to change quickly from fabric covered metal framed biplanes to cantilever stressed skin monoplanes in time for the war with Germany.

The period of improving the same biplane design over and over was now coming to an end, and the Hawker Hurricane and Supermarine Spitfire finally started to supplant the Gloster Gladiator and Hawker Fury biplanes but many of the former remained in front-line service well past the start of World War II. While not a combatant themselves in Spain, they absorbed many of the lessons learned in time to use them.

The Spanish Civil War also provided an opportunity for updating fighter tactics. One of the innovations to result from the aerial warfare experience this conflict provided was the development of the "finger-four" formation by the German pilot Werner Mölders. Each fighter squadron (German: Staffel) was divided into several flights (Schwärme) of four aircraft. Each Schwarm was divided into two Rotten, which was a pair of aircraft. Each Rotte was composed of a leader and a wingman. This flexible formation allowed the pilots to maintain greater situational awareness, and the two Rotten could split up at any time and attack on their own. The finger-four would become widely adopted as the fundamental tactical formation over the course of World War.[clarification needed]

World War II featured fighter combat on a larger scale than any other conflict to date. German Field Marshal Erwin Rommel noted the effect of airpower: "Anyone who has to fight, even with the most modern weapons, against an enemy in complete command of the air, fights like a savage against modern European troops, under the same handicaps and with the same chances of success." Throughout the war, fighters performed their conventional role in establishing air superiority through combat with other fighters and through bomber interception, and also often performed roles such as tactical air support and reconnaissance.

Fighter design varied widely among combatants. The Japanese and Italians favored lightly armed and armored but highly maneuverable designs such as the Japanese Nakajima Ki-27, Nakajima Ki-43 and Mitsubishi A6M Zero and Italy's Fiat G.50 and Macchi MC.200. In contrast, designers in the United Kingdom, Germany, the Soviet Union, and the United States believed that the increased speed of fighter aircraft would create g-forces unbearable to pilots who attempted maneuvering dogfights typical of the First World War, and their fighters were instead optimized for speed and firepower. In practice, while light, highly maneuverable aircraft did possess some advantages in fighter-versus-fighter combat, those could usually be overcome by sound tactical doctrine, and the design approach of the Italians and Japanese made their fighters ill-suited as interceptors or attack aircraft.

During the invasion of Poland and the Battle of France, Luftwaffe fighters—primarily the Messerschmitt Bf 109—held air superiority, and the Luftwaffe played a major role in German victories in these campaigns. During the Battle of Britain, however, British Hurricanes and Spitfires proved roughly equal to Luftwaffe fighters. Additionally Britain's radar-based Dowding system directing fighters onto German attacks and the advantages of fighting above Britain's home territory allowed the RAF to deny Germany air superiority, saving the UK from possible German invasion and dealing the Axis a major defeat early in the Second World War.

This Supermarine Spitfire XVI was typical of World War II fighters optimized for high level speeds and good climb rates.

On the Eastern Front, Soviet fighter forces were overwhelmed during the opening phases of Operation Barbarossa. This was a result of the tactical surprise at the outset of the campaign, the leadership vacuum within the Soviet military left by the Great Purge, and the general inferiority of Soviet designs at the time, such as the obsolescent I-15biplane and the I-16. More modern Soviet designs, including the MiG-3, LaGG-3 and Yak-1, had not yet arrived in numbers and in any case were still inferior to the Messerschmitt Bf 109. As a result, during the early months of these campaigns, Axis air forces destroyed large numbers of Red Air Force aircraft on the ground and in one-sided dogfights.

In the later stages on the Eastern Front, Soviet training and leadership improved, as did their equipment.Since 1942 Soviet designs such as the Yakovlev Yak-9 and Lavochkin La-5 had performance comparable to the German Bf 109 and Focke-Wulf Fw 190. Also, significant numbers of British, and later U.S., fighter aircraft were supplied to aid the Soviet war effort as part of Lend-Lease, with the Bell P-39 Airacobra proving particularly effective in the lower-altitude combat typical of the Eastern Front. The Soviets were also helped indirectly by the American and British bombing campaigns, which forced the Luftwaffe to shift many of its fighters away from the Eastern Front in defense against these raids. The Soviets increasingly were able to challenge the Luftwaffe, and while the Luftwaffe maintained a qualitative edge over the Red Air Force for much of the war, the increasing numbers and efficacy of the Soviet Air Force were critical to the Red Army's efforts at turning back and eventually annihilating the Wehrmacht.

A modern reproduction of the Messerschmitt Me 262 in flight in 2006. The first two operational turbojet aircraft, the Me 262 and then the Gloster Meteor entered service in 1944.

Meanwhile, air combat on the Western Front had a much different character. Much of this combat was centered around the strategic bombing campaigns of the RAF and the USAAF against German industry intended to wear down the Luftwaffe. Axis fighter aircraft focused on defending against Allied bombers while Allied fighters' main role was as bomber escorts. The RAF raided German cities at night, and both sides developed radar-equipped night fighters for these battles. The Americans, in contrast, flew daylight bombing raids into Germany. Unescorted Consolidated B-24 Liberators and Boeing B-17 Flying Fortress bombers, however, proved unable to fend off German interceptors (primarily Bf 109s and Fw 190s). With the later arrival of long range fighters, particularly the North American P-51 Mustang, American fighters were able to escort far into Germany on daylight raids and established control of the skies over Western Europe.

By the time of Operation Overlord in June 1944, the Allies had gained near complete air superiority over the Western Front. This cleared the way both for intensified strategic bombing of German cities and industries, and for the tactical bombing of battlefield targets. With the Luftwaffe largely cleared from the skies, Allied fighters increasingly served as attack aircraft.

Allied fighters, by gaining air superiority over the European battlefield, played a crucial role in the eventual defeat of the Axis, which Reichmarshal Hermann Göring, commander of the German Luftwaffe summed up when he said: "When I saw Mustangs over Berlin, I knew the jig was up."[15]

By mid-1942, the Allies began to regroup and while some Allied aircraft such as the Brewster Buffalo and the P-39 were hopelessly outclassed by fighters like Japan's Zero, others such as the Army's P-40 and the Navy's Wildcat possessed attributes such as superior firepower, ruggedness and dive speed, and the Allies soon developed tactics (such as the Thach weave) to take advantage of these strengths. These changes soon paid dividends, as the Allied ability to deny Japan air superiority was critical to their victories at Coral Sea, Midway, Guadalcanal and New Guinea. In China, the Flying Tigers also used the same tactics with some success, although they were unable to stem the tide of Japanese advances there.

Captured Nakajima Ki-43-I under evaluation by the Allies

By 1943, the Allies began to gain the upper hand in the Pacific Campaign's air campaigns. Several factors contributed to this shift. First, second-generation Allied fighters such as the Hellcat and the P-38, and later the Corsair, the P-47 and the P-51, began arriving in numbers. These fighters outperformed Japanese fighters in all respects except maneuverability. Other problems with Japan's fighter aircraft also became apparent as the war progressed, such as their lack of armor and light armament, which made them inadequate as bomber interceptors or ground-attack planes – roles Allied fighters excelled at. Most importantly, Japan's training program failed to provide enough well-trained pilots to replace losses. In contrast, the Allies improved both the quantity and quality of pilots graduating from their training programs.

By mid-1944, Allied fighters had gained air superiority throughout the theater, which would not be contested again during the war. The extent of Allied quantitative and qualitative superiority by this point in the war was demonstrated during the Battle of the Philippine Sea, a lopsided Allied victory in which Japanese fliers were downed in such numbers and with such ease that American fighter pilots likened it to a great turkey shoot.

Grumman F6F-3 Hellcats, May 1943

Late in the war, Japan did begin to produce new fighters such as the Nakajima Ki-84 and the Kawanishi N1K to replace the venerable Zero, but these were produced only in small numbers, and in any case by that time Japan lacked trained pilots or sufficient fuel to mount a sustained challenge to Allied fighters. During the closing stages of the war, Japan's fighter arm could not seriously challenge raids over Japan by American B-29s, and was largely relegated to Kamikaze tactics.

Fighter technology advanced rapidly during the Second World War. Piston-engines, which powered the vast majority of World War II fighters, grew more powerful: at the beginning of the war fighters typically had engines producing between 1,000 hp (750 kW) and 1,400 hp (1,000 kW), while by the end of the war many could produce over 2,000 hp (1,500 kW). For example, the Spitfire, one of the few fighters in continuous production throughout the war, was in 1939 powered by a 1,030 hp (770 kW) Merlin II, while variants produced in 1945 were equipped with the 2,035 hp (1,517 kW) Griffon 61. Nevertheless, these fighters could only achieve modest increases in top speed due to problems of compressibility created as aircraft and their propellers approached the sound barrier, and it was apparent that propeller-driven aircraft were approaching the limits of their performance. German jet and rocket-powered fighters entered combat in 1944, too late to impact the war's outcome. The same year the Allies' only operational jet fighter, the Gloster Meteor, also entered service.

Armament also advanced during the war. The rifle-caliber machine guns that were common on prewar fighters could not easily down the more rugged warplanes of the era. Air forces began to replace or supplement them with cannons, which fired explosive shells that could blast a hole in an enemy aircraft – rather than relying on kinetic energy from a solid bullet striking a critical component of the aircraft, such as a fuel line or control cable, or the pilot. Cannons could bring down even heavy bombers with just a few hits, but their slower rate of fire made it difficult to hit fast-moving fighters in a dogfight. Eventually, most fighters mounted cannons, sometimes in combination with machine guns.

The British epitomized this shift. Their standard early war fighters mounted eight .303-inch (7.7 mm) calibre machine guns, but by mid-war they often featured a combination of machine guns and 20 mm cannons, and late in the war often only cannons. The Americans, in contrast, had problems producing a native cannon design, so instead placed multiple .50 caliber (12.7 mm) heavy machine guns on their fighters. Fighters were also increasingly fitted with bomb racks and air-to-surface ordnance such as bombs or rockets beneath their wings, and pressed into close air support roles as fighter-bombers. Although they carried less ordnance than light and medium bombers, and generally had a shorter range, they were cheaper to produce and maintain and their maneuverability made it easier for them to hit moving targets such as motorized vehicles. Moreover, if they encountered enemy fighters, their ordnance (which reduced lift and increased drag and therefore decreased performance) could be jettisoned and they could engage the enemy fighters, which eliminated the need for the fighter escorts that bombers required. Heavily armed and sturdily constructed fighters such as Germany's Focke-Wulf Fw 190, Britain's Hawker Typhoon and Hawker Tempest, and America's P-40, Corsair, P-47 and P-38 all excelled as fighter-bombers, and since the Second World War ground attack has been an important secondary capability of many fighters.

A Northrop P-61 Black Widow of 419th Night Fighter Squadron

World War II also saw the first use of airborne radar on fighters. The primary purpose of these radars was to help night fighters locate enemy bombers and fighters. Because of the bulkiness of these radar sets, they could not be carried on conventional single-engined fighters and instead were typically retrofitted to larger heavy fighters or light bombers such as Germany's Messerschmitt Bf 110 and Junkers Ju 88, Britain's Mosquito and Beaufighter, and America's A-20, which then served as night fighters. The Northrop P-61 Black Widow, a purpose-built night fighter, was the only fighter of the war that incorporated radar into its original design. Britain and America cooperated closely in the development of airborne radar, and Germany's radar technology generally lagged slightly behind Anglo-American efforts, while other combatants developed few radar-equipped fighters.

Several prototype fighter programs begun early in 1945 continued on after the war and led to advanced piston-engine fighters that entered production and operational service in 1946. A typical example is the Lavochkin La-9 'Fritz', which was an evolution of the successful wartime Lavochkin La-7 'Fin'. Working through a series of prototypes, the La-120, La-126 and La-130, the Lavochkin design bureau sought to replace the La-7's wooden airframe with a metal one, as well as fit a laminar-flow wing to improve maneuver performance, and increased armament. The La-9 entered service in August 1946 and was produced until 1948; it also served as the basis for the development of a long-range escort fighter, the La-11 'Fang', of which nearly 1200 were produced 1947–1951. Over the course of the Korean War, however, it became obvious that the day of the piston-engined fighter was coming to a close and that the future would lie with the jet fighter.

A Ryan FR-1 Fireball of VF-66 at NAS North Island, 1945. This aircraft featured a piston engine for range and a jet engine in the tail for speed.

This period also witnessed experimentation with jet-assisted piston engine aircraft. La-9 derivatives included examples fitted with two underwing auxiliary pulsejet engines (the La-9RD) and a similarly mounted pair of auxiliary ramjet engines (the La-138); however, neither of these entered service. One that did enter service – with the U.S. Navy in March 1945 – was the Ryan FR-1 Fireball; production was halted with the war's end on VJ-Day, with only 66 having been delivered, and the type was withdrawn from service in 1947. The USAAF had ordered its first 13 mixed turboprop-turbojet-powered pre-production prototypes of the Consolidated Vultee XP-81 fighter, but this program was also canceled by VJ Day, with 80% of the engineering work completed.

The first rocket-powered aircraft was the Lippisch Ente, which made a successful maiden flight in March 1928.[18] The only pure rocket aircraft ever mass-produced was the Messerschmitt Me 163B Komet in 1944, one of several German World War II projects aimed at developing high speed, point-defense aircraft.[19] Later variants of the Me 262 (C-1a and C-2b) were also fitted with "mixed-power" jet/rocket powerplants, while earlier models were fitted with rocket boosters, but were not mass-produced with these modifications.[20]

The USSR experimented with a rocket-powered interceptor in the years immediately following World War II, the Mikoyan-Gurevich I-270. Only two were built.

In the 1950s, the British developed mixed-power jet designs employing both rocket and jet engines to cover the performance gap that existed in turbojet designs. The rocket was the main engine for delivering the speed and height required for high-speed interception of high-level bombers and the turbojet gave increased fuel economy in other parts of flight, most notably to ensure the aircraft was able to make a powered landing rather than risking an unpredictable gliding return. The Saunders-Roe SR.53 was a successful design, and was planned for production when economics forced the British to curtail most aircraft programs in the late 1950s. Furthermore, rapid advancements in jet engine technology rendered mixed-power aircraft designs like Saunders-Roe's SR.53 (and the following SR.177) obsolete. The American Republic XF-91 Thunderceptor (the first U.S. fighter to exceed Mach 1 in level flight) met a similar fate for the same reason, and no hybrid rocket-and-jet-engine fighter design has ever been placed into service. The only operational implementation of mixed propulsion was Rocket-Assisted Take Off (RATO), a system rarely used in fighters, such as with the zero-length launch, RATO-based takeoff scheme from special launch platforms, tested out by both the United States and the Soviet Union, and made obsolete with advancements in surface-to-air missile technology.

It has become common in the aviation community to classify jet fighters by "generations" for historical purposes.[21] There are no official definitions of these generations; rather, they represent the notion that there are stages in the development of fighter design approaches, performance capabilities, and technological evolution. Also other authors have packed the fighters into different generations. For example, Richard P. Hallion of the Secretary of the Air Force's Action Group classified the F-16 as a sixth generation jet fighter.[22]

The timeframes associated with each generation are inexact and are only indicative of the period during which their design philosophies and technology employment enjoyed a prevailing influence on fighter design and development. These timeframes also encompass the peak period of service entry for such aircraft.

The first generation of jet fighters comprised the initial, subsonic jet fighter designs introduced late in World War II and in the early post-war period. They differed little from their piston-engined counterparts in appearance, and many employed unswept wings. Guns and cannon remained the principal armament. The need to obtain a decisive advantage in maximum speed pushed the development of turbojet-powered aircraft forward. Top speeds for fighters rose steadily throughout World War II as more powerful piston engines were developed, and was approaching transonic flight speeds where the efficiency of propellers drops off, making further speed increases nearly impossible.

The first jets were developed during World War II and saw combat in the last two years of the war. Messerschmitt developed the first operational jet fighter, the Me 262A, primarily serving with JG 7, the world's first jet fighter wing. It was considerably faster than contemporary piston-driven aircraft, and in the hands of a competent pilot, was quite difficult for Allied pilots to defeat. The design was never deployed in numbers sufficient to stop the Allied air campaign, and a combination of fuel shortages, pilot losses, and technical difficulties with the engines kept the number of sorties low. Nevertheless, the Me 262 indicated the obsolescence of piston-driven aircraft. Spurred by reports of the German jets, Britain's Gloster Meteor entered production soon after and the two entered service around the same time in 1944. Meteors were commonly used to intercept the V-1 flying bomb, as they were faster than available piston-engined fighters at the low altitudes the flying bombs were flying. Nearer the end of World War II, the first military jet-powered light fighter design, the Heinkel He 162A Spatz (sparrow), was intended to be a simple jet fighter for German home defense, with a few examples seeing squadron service with JG 1 by April 1945. By the end of the war almost all work on piston-powered fighters had ended. A few designs combining piston and jet engines for propulsion – such as the Ryan FR Fireball – saw brief use, but by the end of the 1940s virtually all new fighters were jet-powered.

Despite their advantages, the early jet fighters were far from perfect. The operational lifespan of turbines were very short and engines were temperamental, while power could be adjusted only slowly and acceleration was poor (even if top speed was higher) compared to the final generation of piston fighters. Many squadrons of piston-engined fighters were retained until the early to mid-1950s, even in the air forces of the major powers (though the types retained were the best of the World War II designs). Innovations including ejection seats, air brakes and all-moving tailplanes became widespread in this period.

The Americans began using jet fighters operationally post-war, the wartime Bell P-59 having proven itself a failure. The Lockheed P-80 Shooting Star (soon re-designated F-80) was less elegant than the swept-wing Me 262, but had a cruise speed (660 km/h (410 mph)) as high as the maximum speed attainable by many piston-engined fighters. The British designed several new jets, including the distinctive single-engined twin boomde Havilland Vampire which was sold to the air forces of many nations.

The British transferred the technology of the Rolls-Royce Nene jet engine to the Soviets, who soon put it to use in their advanced Mikoyan-Gurevich MiG-15 fighter, which used fully swept wings that allowed flying closer to the speed of sound than straight-winged designs such as the F-80. Its top speed of 1,075 km/h (668 mph) proved quite a shock to the American F-80 pilots who encountered them in the Korean War, along with their armament of two 23 mm cannons and a single 37 mm cannon. Nevertheless, in the first jet-versus-jet dogfight, which occurred during the Korean War on 8 November 1950, an F-80 shot down two North Korean MiG-15s.

The Americans responded by rushing their own swept-wing fighter – the North American F-86 Sabre – into battle against the MiGs, which had similar transsonic performance. The two aircraft had different strengths and weaknesses, but were similar enough that victory could go either way. While the Sabres were focused primarily on downing MiGs and scored favourably against those flown by the poorly trained North Koreans, the MiGs in turn decimated US bomber formations and forced the withdrawal of numerous American types from operational service.

The development of second-generation fighters was shaped by technological breakthroughs, lessons learned from the aerial battles of the Korean War, and a focus on conducting operations in a nuclear warfare environment. Technological advances in aerodynamics, propulsion and aerospace building materials (primarily aluminium alloys) permitted designers to experiment with aeronautical innovations, such as swept wings, delta wings, and area-ruled fuselages. Widespread use of afterburning turbojet engines made these the first production aircraft to break the sound barrier, and the ability to sustain supersonic speeds in level flight became a common capability amongst fighters of this generation.

Fighter designs also took advantage of new electronics technologies that made effective radars small enough to carry aboard smaller aircraft. Onboard radars permitted detection of enemy aircraft beyond visual range, thereby improving the handoff of targets by longer-ranged ground-based warning and tracking radars. Similarly, advances in guided missile development allowed air-to-air missiles to begin supplementing the gun as the primary offensive weapon for the first time in fighter history. During this period, passive-homing infrared-guided (IR) missiles became commonplace, but early IR missile sensors had poor sensitivity and a very narrow field of view (typically no more than 30°), which limited their effective use to only close-range, tail-chase engagements. Radar-guided (RF) missiles were introduced as well, but early examples proved unreliable. These semi-active radar homing (SARH) missiles could track and intercept an enemy aircraft "painted" by the launching aircraft's onboard radar. Medium- and long-range RF air-to-air missiles promised to open up a new dimension of "beyond-visual-range" (BVR) combat, and much effort was placed in further development of this technology.

The prospect of a potential third world war featuring large mechanized armies and nuclear weapon strikes led to a degree of specialization along two design approaches: interceptors, such as the English Electric Lightning and Mikoyan-Gurevich MiG-21F; and fighter-bombers, such as the Republic F-105 Thunderchief and the Sukhoi Su-7B. Dogfighting, per se, was de-emphasized in both cases. The interceptor was an outgrowth of the vision that guided missiles would completely replace guns and combat would take place at beyond visual ranges. As a result, interceptors were designed with a large missile payload and a powerful radar, sacrificing agility in favor of high speed, altitude ceiling and rate of climb. With a primary air defense role, emphasis was placed on the ability to intercept strategic bombers flying at high altitudes. Specialized point-defense interceptors often had limited range and little, if any, ground-attack capabilities. Fighter-bombers could swing, between air superiority and ground-attack roles, and were often designed for a high-speed, low-altitude dash to deliver their ordnance. Television- and IR-guided air-to-surface missiles were introduced to augment traditional gravity bombs, and some were also equipped to deliver a nuclear bomb.

The third generation witnessed continued maturation of second-generation innovations, but it is most marked by renewed emphases on maneuverability and traditional ground-attack capabilities. Over the course of the 1960s, increasing combat experience with guided missiles demonstrated that combat would devolve into close-in dogfights. Analog avionics began to appear, replacing older "steam-gauge" cockpit instrumentation. Enhancements to the aerodynamic performance of third-generation fighters included flight control surfaces such as canards, powered slats, and blown flaps. A number of technologies would be tried for Vertical/Short Takeoff and Landing, but thrust vectoring would be successful on the Harrier.

Growth in air combat capability focused on the introduction of improved air-to-air missiles, radar systems, and other avionics. While guns remained standard equipment (early models of F-4 being a notable exception), air-to-air missiles became the primary weapons for air superiority fighters, which employed more sophisticated radars and medium-range RF AAMs to achieve greater "stand-off" ranges, however, kill probabilities proved unexpectedly low for RF missiles due to poor reliability and improved electronic countermeasures (ECM) for spoofing radar seekers. Infrared-homing AAMs saw their fields of view expand to 45°, which strengthened their tactical usability. Nevertheless, the low dogfight loss-exchange ratios experienced by American fighters in the skies over Vietnam led the U.S. Navy to establish its famous "TOPGUN" fighter weapons school, which provided a graduate-level curriculum to train fleet fighter pilots in advanced Air Combat Maneuvering (ACM) and Dissimilar Air Combat Training (DACT) tactics and techniques.

This era also saw an expansion in ground-attack capabilities, principally in guided missiles, and witnessed the introduction of the first truly effective avionics for enhanced ground attack, including terrain-avoidance systems. Air-to-surface missiles (ASM) equipped with electro-optical (E-O) contrast seekers – such as the initial model of the widely used AGM-65 Maverick – became standard weapons, and laser-guided bombs (LGBs) became widespread in effort to improve precision-attack capabilities. Guidance for such precision-guided munitions (PGM) was provided by externally mounted targeting pods, which were introduced in the mid-1960s.

It also led to the development of new automatic-fire weapons, primarily chain-guns that use an electric motor to drive the mechanism of a cannon. This allowed a plane to carry a single multi-barrel weapon (such as the 20 mm Vulcan), and provided greater accuracy and rates of fire. Powerplant reliability increased and jet engines became "smokeless" to make it harder to sight aircraft at long distances.

Dedicated ground-attack aircraft (like the Grumman A-6 Intruder, SEPECAT Jaguar and LTV A-7 Corsair II) offered longer range, more sophisticated night attack systems or lower cost than supersonic fighters. With variable-geometry wings, the supersonic F-111 introduced the Pratt & Whitney TF30, the first turbofan equipped with afterburner. The ambitious project sought to create a versatile common fighter for many roles and services. It would serve well as an all-weather bomber, but lacked the performance to defeat other fighters. The McDonnell F-4 Phantom was designed around radar and missiles as an all-weather interceptor, but emerged as a versatile strike bomber nimble enough to prevail in air combat, adopted by the U.S. Navy, Air Force and Marine Corps. Despite numerous shortcomings that would be not be fully addressed until newer fighters, the Phantom claimed 280 aerial kills, more than any other U.S. fighter over Vietnam.[23] With range and payload capabilities that rivaled that of World War II bombers such as B-24 Liberator, the Phantom would become a highly successful multirole aircraft.

Fourth-generation fighters continued the trend towards multirole configurations, and were equipped with increasingly sophisticated avionics and weapon systems. Fighter designs were significantly influenced by the Energy-Maneuverability (E-M) theory developed by Colonel John Boyd and mathematician Thomas Christie, based upon Boyd's combat experience in the Korean War and as a fighter tactics instructor during the 1960s. E-M theory emphasized the value of aircraft specific energy maintenance as an advantage in fighter combat. Boyd perceived maneuverability as the primary means of getting "inside" an adversary's decision-making cycle, a process Boyd called the "OODA loop" (for "Observation-Orientation-Decision-Action"). This approach emphasized aircraft designs that were capable of performing "fast transients" – quick changes in speed, altitude, and direction – as opposed to relying chiefly on high speed alone.

The F-16's maneuverability was further enhanced by its slight aerodynamic instability. This technique, called "relaxed static stability" (RSS), was made possible by introduction of the "fly-by-wire" (FBW) flight control system (FLCS), which in turn was enabled by advances in computers and system integration techniques. Analog avionics, required to enable FBW operations, became a fundamental requirement and began to be replaced by digital flight control systems in the latter half of the 1980s. Likewise, Full Authority Digital Engine Controls (FADEC) to electronically manage powerplant performance was introduced with the Pratt & Whitney F100 turbofan. The F-16's sole reliance on electronics and wires to relay flight commands, instead of the usual cables and mechanical linkage controls, earned it the sobriquet of "the electric jet". Electronic FLCS and FADEC quickly became essential components of all subsequent fighter designs.

Another revolution came in the form of a stronger reliance on ease of maintenance, which led to standardisation of parts, reductions in the numbers of access panels and lubrication points, and overall parts reduction in more complicated equipment like the engines. Some early jet fighters required 50 man-hours of work by a ground crew for every hour the aircraft was in the air; later models substantially reduced this to allow faster turn-around times and more sorties in a day. Some modern military aircraft only require 10 man-hours of work per hour of flight time, and others are even more efficient.

Unlike interceptors of the previous eras, most fourth-generation air-superiority fighters were designed to be agile dogfighters (although the Mikoyan MiG-31 and Panavia Tornado ADV are notable exceptions). The continually rising cost of fighters, however, continued to emphasize the value of multirole fighters. The need for both types of fighters led to the "high/low mix" concept, which envisioned a high-capability and high-cost core of dedicated air-superiority fighters (like the F-15 and Su-27) supplemented by a larger contingent of lower-cost multi-role fighters (such as the F-16 and MiG-29).

A typical US Air Force fighter wing of the period might contain a mix of one air superiority squadron (F-15C), one strike fighter squadron (F-15E), and two multirole fighter squadrons (F-16C).[24]

Perhaps the most novel technology introduced for combat aircraft was stealth, which involves the use of special "low-observable" (L-O) materials and design techniques to reduce the susceptibility of an aircraft to detection by the enemy's sensor systems, particularly radars. The first stealth aircraft introduced were the Lockheed F-117 Nighthawk attack aircraft (introduced in 1983) and the Northrop Grumman B-2 Spirit bomber (first flew in 1989). Although no stealthy fighters per se appeared among the fourth generation, some radar-absorbent coatings and other L-O treatments developed for these programs are reported to have been subsequently applied to fourth-generation fighters.

The end of the Cold War in 1991 led many governments to significantly decrease military spending as a "peace dividend". Air force inventories were cut. Research and development programs working on "fifth-generation" fighters took serious hits. Many programs were canceled during the first half of the 1990s, and those that survived were "stretched out". While the practice of slowing the pace of development reduces annual investment expenses, it comes at the penalty of increased overall program and unit costs over the long-term. In this instance, however, it also permitted designers to make use of the tremendous achievements being made in the fields of computers, avionics and other flight electronics, which had become possible largely due to the advances made in microchip and semiconductor technologies in the 1980s and 1990s. This opportunity enabled designers to develop fourth-generation designs – or redesigns – with significantly enhanced capabilities. These improved designs have become known as "Generation 4.5" fighters, recognizing their intermediate nature between the 4th and 5th generations, and their contribution in furthering development of individual fifth-generation technologies.

"Half-generation" designs are either based on existing airframes or are based on new airframes following similar design theory to previous iterations; however, these modifications have introduced the structural use of composite materials to reduce weight, greater fuel fractions to increase range, and signature reduction treatments to achieve lower RCS compared to their predecessors. Prime examples of such aircraft, which are based on new airframe designs making extensive use of carbon-fibre composites, include the Eurofighter Typhoon, Dassault Rafale, and Saab JAS 39 Gripen.

4.5 generation fighters first entered service in the early 1990s, and most of them are still being produced and evolved. It is quite possible that they may continue in production alongside fifth-generation fighters due to the expense of developing the advanced level of stealth technology needed to achieve aircraft designs featuring very low observables (VLO), which is one of the defining features of fifth-generation fighters. Of the 4.5th generation designs, the Strike Eagle, Super Hornet, Typhoon, Gripen, and Rafale have been used in combat.

The U.S. government has defined 4.5 generation fighter aircraft as those that "(1) have advanced capabilities, including— (A) AESA radar; (B) high capacity data-link; and (C) enhanced avionics; and (2) have the ability to deploy current and reasonably foreseeable advanced armaments."[25][26]

Currently the cutting edge of fighter design, fifth-generation fighters are characterized by being designed from the start to operate in a network-centric combat environment, and to feature extremely low, all-aspect, multi-spectral signatures employing advanced materials and shaping techniques. They have multifunction AESA radars with high-bandwidth, low-probability of intercept (LPI) data transmission capabilities. The Infra-red search and track sensors incorporated for air-to-air combat as well as for air-to-ground weapons delivery in the 4.5th generation fighters are now fused in with other sensors for Situational Awareness IRST or SAIRST, which constantly tracks all targets of interest around the aircraft so the pilot need not guess when he glances. These sensors, along with advanced avionics, glass cockpits, helmet-mounted sights (not currently on F-22), and improved secure, jamming-resistant LPI datalinks are highly integrated to provide multi-platform, multi-sensor data fusion for vastly improved situational awareness while easing the pilot's workload.[27] Avionics suites rely on extensive use of very high-speed integrated circuit (VHSIC) technology, common modules, and high-speed data buses. Overall, the integration of all these elements is claimed to provide fifth-generation fighters with a "first-look, first-shot, first-kill capability".

A key attribute of fifth-generation fighters is a small radar cross-section. Great care has been taken in designing its layout and internal structure to minimize RCS over a broad bandwidth of detection and tracking radar frequencies; furthermore, to maintain its VLO signature during combat operations, primary weapons are carried in internal weapon bays that are only briefly opened to permit weapon launch. Furthermore, stealth technology has advanced to the point where it can be employed without a tradeoff with aerodynamics performance, in contrast to previous stealth efforts. Some attention has also been paid to reducing IR signatures, especially on the F-22. Detailed information on these signature-reduction techniques is classified, but in general includes special shaping approaches, thermoset and thermoplastic materials, extensive structural use of advanced composites, conformal sensors, heat-resistant coatings, low-observable wire meshes to cover intake and cooling vents, heat ablating tiles on the exhaust troughs (seen on the Northrop YF-23), and coating internal and external metal areas with radar-absorbent materials and paint (RAM/RAP).

The AESA radar offers unique capabilities for fighters (and it is also quickly becoming essential for Generation 4.5 aircraft designs, as well as being retrofitted onto some fourth-generation aircraft). In addition to its high resistance to ECM and LPI features, it enables the fighter to function as a sort of "mini-AWACS," providing high-gain electronic support measures (ESM) and electronic warfare (EW) jamming functions. Other technologies common to this latest generation of fighters includes integrated electronic warfare system (INEWS) technology, integrated communications, navigation, and identification (CNI) avionics technology, centralized "vehicle health monitoring" systems for ease of maintenance, fiber optics data transmission, stealth technology and even hovering capabilities. Maneuver performance remains important and is enhanced by thrust-vectoring, which also helps reduce takeoff and landing distances. Supercruise may or may not be featured; it permits flight at supersonic speeds without the use of the afterburner – a device that significantly increases IR signature when used in full military power.

Other countries have initiated fifth-generation fighter development projects, with Russia's Sukhoi Su-57 and Mikoyan LMFS. In December 2010, it was discovered that China is developing the 5th generation fighter Chengdu J-20.[28] The J-20 took its maiden flight in January 2011. The Shenyang J-31 took its maiden flight on 31 October 2012.[29] Japan is exploring its technical feasibility to produce fifth-generation fighters.India is developing the Advanced Medium Combat Aircraft (AMCA) ;a medium weight stealth fighter jet designated to enter into serial production by late 2030s. India also had initiated a joint fifth generation heavy fighter with Russia called the FGFA. As of 2018[update] May, the project is suspected to have not yielded desired progress or results for India and has been put on hold or dropped altogether.[30]
Other countries considering fielding an indigenous or semi-indigenous advanced fifth generation aircraft include Korea, Sweden and Turkey.

Throughout the history of air combat, fighters which, by surprise or maneuver, attain a good firing position have achieved the kill about one third to one half the time, no matter what weapons were carried.[40] The only major historic exception to this has been the low effectiveness shown by guided missiles in the first one to two decades of their existence.[41][42]

From WWI to the present fighter aircraft have featured machine guns and automatic cannons as weapons, and they are still considered as essential back-up weapons today. The power of air-to-air guns has increased greatly over time, and has kept them relevant in the guided missile era.[43] In WWI two rifle calibre machine guns was the typical armament producing a weight of fire of about 0.4 kg (0.88 lb) per second. The standard WWII American fighter armament of six 0.50-cal (12.7mm) machine guns fired a bullet weight of approximately 3.7 kg/sec (8.1 lbs/sec), at a muzzle velocity of 856 m/s (2,810 ft/s). British and German aircraft tended to use a mix of machine guns and autocannon, the latter firing explosive projectiles. The modern M61 Vulcan 20 mm rotating barrel Gatling gun that is standard on current American fighters fires a projectile weight of about 10 kg/s (22 lb/s), nearly three times that of six 0.50-cal machine guns, with higher velocity of 1,052 m/s (3450 ft/s) supporting a flatter trajectory, and with exploding projectiles.[44] Modern fighter gun systems also feature ranging radar and lead computing electronic gun sights to ease the problem of aim point to compensate for projectile drop and time of flight (target lead) in the complex three dimensional maneuvering of air-to-air combat. However, getting in position to use the guns is the challenge. The range of guns is longer than in the past but still quite limited compared to missiles, with modern gun systems having a maximum effective range of approximately 1,000 meters.[45] High probability of kill also requires firing to usually occur from the rear hemisphere of the target.[46] Despite these limits, when pilots are well trained in air-to-air gunnery and these conditions are satisfied, gun systems are tactically effective and highly cost efficient. The cost of a gun firing pass is far less than firing a missile, and the projectiles are not subject to the thermal and electronic countermeasures than can sometimes defeat missiles. When the enemy can be approached to within gun range, the lethality of guns is approximately a 25% to 50% chance of "kill per firing pass".[47]

The range limitations of guns, and the desire to overcome large variations in fighter pilot skill and thus achieve higher force effectiveness, led to the development of the guided air-to-air missile. There are two main variations, heat-seeking (infrared homing), and radar guided. Radar missiles are typically several times heavier and more expensive than heat-seekers, but with longer range, greater destructive power, and ability to track through clouds.

The highly successful AIM-9 Sidewinder heat-seeking (infrared homing) short-range missile was developed by the United States Navy in the 1950s. These small missiles are easily carried by lighter fighters, and provide effective ranges of approximately 10 to 35 km (~6 to 22 miles). Beginning with the AIM-9L in 1977, subsequent versions of Sidewinder have added all-aspect capability, the ability to use the lower heat of air to skin friction on the target aircraft to track from the front and sides. The latest (2003 service entry) AIM-9X also features "off-boresight" and "lock on after launch" capabilities, which allow the pilot to make a quick launch of a missile to track a target anywhere within the pilot's vision. The AIM-9X development cost was U.S. $3 billion in mid to late 1990s dollars,[48] and 2015 per unit procurement cost is $0.6 million each. The missile weighs 85.3 kg (188 lbs), and has a maximum range of 35 km (22 miles) at higher altitudes. Like most air-to-air missiles, lower altitude range can be as limited as only about one third of maximum due to higher drag and less ability to coast downward.[49]

The effectiveness of heat-seeking missiles was only 7% early in the Vietnam War,[50] but improved to approximately 15%–40% over the course of the war. The AIM-4 Falcon used by the USAF had kill rates of approximately 7% and was considered a failure. The AIM-9B Sidewinder introduced later achieved 15% kill rates, and the further improved AIM-9D and J models reached 19%. The AIM-9G used in the last year of the Vietnam air war achieved 40%.[51] Israel used almost totally guns in the 1967 Six-Day War, achieving 60 kills and 10 losses.[52] However, Israel made much more use of steadily improving heat-seeking missiles in the 1973 Yom Kippur War. In this extensive conflict Israel scored 171 of out of 261 total kills with heat-seeking missiles (65.5%), 5 kills with radar guided missiles (1.9%), and 85 kills with guns (32.6%).[53] The AIM-9L Sidewinder scored 19 kills out of 26 fired missiles (73%) in the 1982 Falklands War.[54] But, in a conflict against opponents using thermal countermeasures, the United States only scored 11 kills out of 48 fired (Pk = 23%) with the follow-on AIM-9M in the 1991 Gulf War.[55]

Radar guided missiles fall into two main missile guidance types. In the historically more common semi-active radar homing case the missile homes in on radar signals transmitted from launching aircraft and reflected from the target. This has the disadvantage that the firing aircraft must maintain radar lock on the target and is thus less free to maneuver and more vulnerable to attack. A widely deployed missile of this type was the AIM-7 Sparrow, which entered service in 1954 and was produced in improving versions until 1997. In more advanced active radar homing the missile is guided to the vicinity of the target by internal data on its projected position, and then “goes active” with an internally carried small radar system to conduct terminal guidance to the target. This eliminates the requirement for the firing aircraft to maintain radar lock, and thus greatly reduces risk. A prominent example is the AIM-120 AMRAAM, which was first fielded in 1991 as the AIM-7 replacement, and which has no firm retirement date as of 2016[update]. The current AIM-120D version has a maximum high altitude range of greater than 160 km (>99 miles), and cost approximately $2.4 million each (2016). As is typical with most other missiles, range at lower altitude may be as little as one third that of high altitude.

In the Vietnam air war radar missile kill reliability was approximately 10% at shorter ranges, and even worse at longer ranges due to reduced radar return and greater time for the target aircraft to detect the incoming missile and take evasive action. At one point in the Vietnam war, the U.S. Navy fired 50 AIM-7 Sparrow radar guided missiles in a row without a hit.[56] Between 1958 and 1982 in five wars there were 2,014 combined heat-seeking and radar guided missile firings by fighter pilots engaged in air-to-air combat, achieving 528 kills, of which 76 were radar missile kills, for a combined effectiveness of 26%. However, only four of the 76 radar missile kills were in the beyond-visual-range mode intended to be the strength of radar guided missiles.[57] The United States invested over $10 billion in air-to-air radar missile technology from the 1950s to the early 1970s.[58] Amortized over actual kills achieved by the U.S. and its allies, each radar guided missile kill thus cost over $130 million. The defeated enemy aircraft were for the most part older MiG-17s, -19s, and -21s, with new cost of $0.3 million to $3 million each. Thus, the radar missile investment over that period far exceeded the value of enemy aircraft destroyed, and furthermore had very little of the intended BVR effectiveness.

However, continuing heavy development investment and rapidly advancing electronic technology led to significant improvement in radar missile reliabilities from the late 1970s onward. Radar guided missiles achieved 75% Pk (9 kills out of 12 shots) in operations in the Gulf War in 1991.[59] The percentage of kills achieved by radar guided missiles also surpassed 50% of total kills for the first time by 1991. Since 1991, 20 of 61 kills worldwide have been beyond-visual-range using radar missiles.[60] Discounting an accidental friendly fire kill, in operational use the AIM-120D (the current main American radar guided missile) has achieved 9 kills out of 16 shots for a 56% Pk. Six of these kills were BVR, out of 13 shots, for a 46% BVR Pk.[61] Though all these kills were against less capable opponents who were not equipped with operating radar, electronic countermeasures, or a comparable weapon themselves, the BVR Pk was a significant improvement from earlier eras. However, a current concern is electronic countermeasures to radar missiles,[62] which are thought to be reducing the effectiveness of the AIM-120D. Some experts believe that as of 2016[update] the European Meteor missile, the Russian K-37M, and the Chinese PL-15 are more resistant to countermeasures and more effective than the AIM-120D.[62]

Now that higher reliabilities have been achieved, both types of missiles allow the fighter pilot to often avoid the risk of the short-range dogfight, where only the more experienced and skilled fighter pilots tend to prevail, and where even the finest fighter pilot can simply get unlucky. Taking maximum advantage of complicated missile parameters in both attack and defense against competent opponents does take considerable experience and skill,[63] but against surprised opponents lacking comparable capability and countermeasures, air-to-air missile warfare is relatively simple. By partially automating air-to-air combat and reducing reliance on gun kills mostly achieved by only a small expert fraction of fighter pilots, air-to-air missiles now serve as highly effective force multipliers.

1.
Lockheed P-38 Lightning
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The Lockheed P-38 Lightning is a World War II-era American piston-engined fighter aircraft. Developed to a United States Army Air Corps requirement, the P-38 had distinctive twin booms, Allied propaganda claimed it had been nicknamed the fork-tailed devil by the Luftwaffe and two planes, one pilot by the Japanese. In the South West Pacific theater, the P-38 was the primary fighter of United States Army Air Forces until the appearance of large numbers of P-51D Mustangs. The P-38 was unusually quiet for a fighter, the exhaust muffled by the turbo-superchargers and it was extremely forgiving and could be mishandled in many ways but the rate of roll in the early versions was too slow for it to excel as a dogfighter. The P-38 was the only American fighter aircraft in production throughout American involvement in the war, at the end of the war, orders for 1,887 more were cancelled. Lockheed designed the P-38 in response to a February 1937 specification from the United States Army Air Corps, Kelsey was looking for a minimum of 1,000 lb of armament. Kelsey and Saville aimed to get a capable fighter, better at dog-fighting. Specifications called for a maximum airspeed of at least 360 mph at altitude, and a climb to 20,000 ft within six minutes, the unbuilt Vultee XP1015 was designed to the same requirement, but was not advanced enough to merit further investigation. A similar single-engine proposal was issued at the time, Circular Proposal X-609. Both proposals required liquid-cooled Allison V-1710 engines with turbo-superchargers and gave points for tricycle landing gear. The Lockheed team chose twin booms to accommodate the tail assembly, engines, the XP-38 gondola mockup was designed to mount two. 50-caliber M2 Browning machine guns with 200 rounds per gun, two. In the YP-38s, a 37 mm M9 autocannon with 15 rounds replaced the T1, the 15 rounds were in three five-round clips, an unsatisfactory arrangement according to Kelsey, and the M9 did not perform reliably in flight. Further armament experiments from March to June 1941 resulted in the P-38E combat configuration of four M2 Browning machine guns, and one Hispano 20 mm autocannon with 150 rounds. Clustering all the armament in the nose was unusual in U. S. aircraft, nose-mounted guns did not suffer from having their useful ranges limited by pattern convergence, meaning that good pilots could shoot much farther. A Lightning could reliably hit targets at any range up to 1,000 yd, whereas the wing guns of other fighters were optimized for a specific range. The rate of fire was about 650 rounds per minute for the 20×110 mm cannon round at a velocity of about 2,887 ft/s. Combined rate of fire was over 4,000 rpm with roughly every sixth projectile a 20 mm shell, the duration of sustained firing for the 20 mm cannon and. 50-caliber machine guns was approximately 14 seconds and 35 seconds, respectively. The P-38 was the first American fighter to make use of stainless steel and smooth

2.
North American F-86 Sabre
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The North American F-86 Sabre, sometimes called the Sabrejet, is a transonic jet fighter aircraft. Considered one of the best and most important fighter aircraft in that war and its success led to an extended production run of more than 7,800 aircraft between 1949 and 1956, in the United States, Japan and Italy. Variants were built in Canada and Australia, the Canadair Sabre added another 1,815 airframes, and the significantly redesigned CAC Sabre, had a production run of 112. The Sabre was by far the most-produced Western jet fighter, with production of all variants at 9,860 units. North American Aviation had produced the propeller-powered P-51 Mustang in World War II, by late 1944, North American proposed its first jet fighter to the U. S. Navy, which became the FJ-1 Fury. It was an unexceptional transitional jet fighter that had a wing derived from the P-51. Initial proposals to meet a United States Army Air Forces requirement for a medium-range, single-seat, in early 1945, North American Aviation submitted four designs. The USAAF selected one design over the others, and granted North American a contract to build three examples of the XP-86, despite the gain in speed, early studies revealed the XP-86 would have the same performance as its rivals, the XP-80 and XP-84. It was also feared that, because these designs were advanced in their development stages. Crucially, the XP-86 would not be able to meet the top speed of 600 mph. The North American F-86 Sabre was the first American aircraft to take advantage of research data seized from the German aerodynamicists at the end of World War II. By 1944, German engineers and designers had established the benefits of swept wings based on designs dating back to 1940. Study of the data showed that a wing would solve their speed problem. Because development of the XP-86 had reached a stage, the idea of changing the sweep of the wing was met with resistance from some senior North American staff. Despite stiff opposition, after results were obtained in wind tunnel tests. Many Sabres had the 6–3 wing retrofitted after combat experience was gained in Korea and this modification changed the wing airfoils to the NACA 0009-64 mod at the root and the NACA0008. 1–64 mod at the tip. Delays caused by the major redesign meant that manufacturing did not begin until after World War II, the XP-86 prototype, which would lead to the F-86 Sabre, was rolled out on 8 August 1947. The maiden flight occurred on 1 October 1947 with George Welch at the controls, flying from Muroc Dry Lake, the United States Air Forces Strategic Air Command had F-86 Sabres in service from 1949 through 1950

3.
Lockheed Martin F-22 Raptor
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The Lockheed Martin F-22 Raptor is a fifth-generation, single-seat, twin-engine, all-weather stealth tactical fighter aircraft developed for the United States Air Force. The aircraft was variously designated F-22 and F/A-22 before it entered service in December 2005 as the F-22A. The Raptors combination of stealth, aerodynamic performance, and situational awareness gives the aircraft unprecedented air combat capabilities, a final procurement tally of 187 operational production aircraft was established in 2009, and the last F-22 was delivered to the USAF in 2012. In 1981 the U. S. Air Force developed a requirement for an Advanced Tactical Fighter as a new air superiority fighter to replace the F-15 Eagle and F-16 Fighting Falcon. Code named Senior Sky, this program was influenced by the emerging threats, including development and proliferation of Soviet Su-27 Flanker-. Each design team produced two prototype air vehicles, one for each of the two engine options, the Lockheed-led team employed thrust vectoring nozzles on YF-22 for enhanced maneuverability in dogfights. The ATFs increasing weight and cost drove out certain requirements during development, side-looking radars were deleted, and the dedicated infra-red search and track system was downgraded from multi-color to single color and then deleted as well. However, space and cooling provisions were retained to allow for future addition of these components, the ejection seat requirement was downgraded from a fresh design to the existing McDonnell Douglas ACES II. After the flight test demonstration and validation of the prototypes, on 23 April 1991, the YF-23 design was considered stealthier and faster, while the YF-22 was more maneuverable. The aviation press speculated that the YF-22 was also adaptable to the U. S. Navys Navalized Advanced Tactical Fighter, but by 1992. F-22 production was split up over many subcontractors across 46 states to increase Congressional support, though this production split may have contributed to increased costs, many capabilities were deferred to post-service upgrades, reducing the initial cost but increasing total program cost. Production supported over 1,000 subcontractors and suppliers and up to 95,000 jobs, the F-22 had several design changes from the YF-22. The swept-back angle of the edge was decreased from 48° to 42°, while the vertical stabilizers were shifted rearward. To improve pilot visibility, the canopy was moved forward 7 inches, the shapes of the wing and stabilator trailing edges were refined to improve aerodynamics, strength, and stealth characteristics. Increasing weight during development caused slight reductions in range and aerodynamic performance, the first F-22, an engineering and manufacturing development aircraft named Raptor 4001, was unveiled at Marietta, Georgia, on 9 April 1997, and first flew on 7 September 1997. In 2006, the Raptors development team, composed of over 1,000 contractors, the F-22 was in production for 15 years, at a rate of roughly two per month during peak production. The USAF originally envisioned ordering 750 ATFs at a cost of $26.2 billion, the 1990 Major Aircraft Review led by Secretary of Defense Dick Cheney reduced this to 648 aircraft beginning in 1996. By 1997, funding instability had further cut the total to 339, in 2004, the Department of Defense further reduced this to 183 operational aircraft, despite the USAFs preference for 381

4.
Military aircraft
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A military aircraft is any fixed-wing or rotary-wing aircraft that is operated by a legal or insurrectionary armed service of any type. Military aircraft can be either combat or non-combat, Combat aircraft are designed to destroy enemy equipment using their own aircraft ordnance, Combat aircraft are normally developed and procured only by military forces. Non-combat aircraft are not designed for combat as their primary function and these mainly operate in support roles, and may be developed by either military forces or civilian organizations. In 1783, when the first practical aircraft were established, they were adopted for military duties. The main role of fighters is destroying enemy aircraft in air-to-air combat, many are fast and highly maneuverable. Escorting bombers or other aircraft is also a common task and they are capable of carrying a variety of weapons, including machine guns, cannons, rockets and guided missiles. Many modern fighters can attack enemy fighters from a great distance, examples of air superiority fighters include the F-22 Raptor. World War II fighters include the British Spitfire, the American P-51 Mustang, an example of an interceptor would be the MiG-25. An example of a fighter is the Messerschmitt Bf 110. The term fighter is also applied to aircraft that have little air-to-air combat capability – for example the A-10 ground-attack aircraft is operated by USAF Fighter squadrons. Bombers are normally larger, heavier, and less maneuverable than fighter aircraft and they are capable of carrying large payloads of bombs, torpedoes or cruise missiles. Bombers are used almost exclusively for ground attacks and not fast or agile enough to take on enemy fighters head-to-head, a few have a single engine and require one pilot to operate and others have two or more engines and require crews of two or more. A limited number of bombers, such as the B-2 Spirit, have stealth capabilities that keep them from being detected by enemy radar, an example of a conventional modern bomber would be the B-52 Stratofortress. An example of a World War II bomber would be a B-17 Flying Fortress, bombers include light bombers, medium bombers, heavy bombers, dive bombers, and torpedo bombers. The U. S. Navy and Marines have traditionally referred to their light, attack aircraft can be used to provide support for friendly ground troops. Some are able to carry conventional or nuclear weapons far behind enemy lines to strike priority ground targets, attack helicopters attack enemy armor and provide close air support for ground troops. An example historical ground-attack aircraft is the Soviet Ilyushin Il-2 Shturmovik, several types of transport airplanes have been armed with sideways firing weapons as gunships for ground attack. These include the AC-47 and AC-130 aircraft, in modern air forces the distinction between bombers, fighter-bombers, and attack aircraft has become blurred

5.
Bomber
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A bomber is a combat aircraft designed to attack ground and sea targets by dropping air-to-ground weaponry, firing torpedoes or deploying air-launched cruise missiles. In 1912, during the First Balkan War, Bulgarian Air Force pilot Christo Toprakchiev suggested the use of aircraft to drop bombs on Turkish positions, captain Simeon Petrov developed the idea and created several prototypes by adapting different types of grenades and increasing their payload. This is deemed to be the first use of an aircraft as a bomber, the first heavier-than-air aircraft purposely designed for bombing were the Italian Caproni Ca 30 and British Bristol T. B.8, both of 1913. The Bristol T. B.8 was an early British single engined biplane built by the Bristol Aeroplane Company, under the command of Charles Rumney Samson, a bombing attack on German gun batteries at Middelkerke, Belgium was executed on 25 November 1914. The dirigible, or airship, was developed in the early 20th century, early airships were prone to disaster, but slowly the airship became more dependable, with a more rigid structure and stronger skin. Prior to the outbreak of war, Zeppelins, a larger and these were the first long range, strategic bombers. Although the German air arm was strong, with a total of 123 airships by the end of the war, they were vulnerable to attack and engine failure, German airships inflicted little damage on all 51 raids, with 557 Britons killed and 1,358 injured. The German Navy lost 53 of its 73 airships, and the German Army lost 26 of its 50 ships, the Caproni Ca 30 was built by Gianni Caproni in Italy. It was a biplane with three 67 kW Gnome rotary engines and first flew in October 1914. Test flights revealed power to be insufficient and the engine layout unworkable, the improved design was bought by the Italian Army and it was delivered in quantity from August 1915. Bombing raids and interdiction operations were carried out by French. Sustained attacks with a view to interrupting the enemys railway communications, in conjunction with the main operations of the Allied Armies. The most important bombers used in World War I were the French Breguet 14, British de Havilland DH-4, German Albatros C. III, the Russian Sikorsky Ilya Muromets, was the first four-engine bomber to equip a dedicated strategic bombing unit during World War I. This heavy bomber was unrivaled in the stages of the war. With engine power as a limitation, combined with the desire for accuracy and other operational factors. By the start of the war included, dive bomber — specially strengthened for vertical diving attacks for greater accuracy. Light bomber, medium bomber and heavy bomber — subjective definitions based on size, torpedo bomber — specialized aircraft armed with torpedoes. Ground attack aircraft — aircraft used against targets on a such as troop or tank concentrations

6.
Attack aircraft
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This class of aircraft is designed mostly for close air support and naval air-to-surface missions, overlapping the tactical bomber mission. Designs dedicated to non-naval roles are often known as ground-attack aircraft, Strike fighters, which have effectively replaced the fighter-bomber and light bomber concepts, also differ little from the broad concept of an attack aircraft. The dedicated attack aircraft as a separate class existed primarily during, the precise implementation varied from country to country, and was handled by a wide variety of designs. In the US and UK, attack aircraft were based on light bombers, sometimes carrying heavier forward-firing weapons like the B-25G. In Germany and USSR, where they were known as schlachtflugzeug or sturmovik, in the late-war era, the fighter-bomber began to take over many attack roles, a change that continued in the post-war era. Jet powered examples were relatively rare, but not unknown, like the Blackburn Buccaneer, the US Navy continued to introduce new aircraft in their A-series, but these were purely light and medium bombers. Since the 1960s, only two dedicated attack aircraft designs have been introduced, the US A-10 Thunderbolt II and Soviet Sukhoi Su-25 Frogfoot. One oddity belonging to class is the AC-130, which features as its primary armament high-caliber artillery guns adapted for aircraft use. A variety of attack aircraft exist, usually based on adapted trainers or other light fixed-wing aircraft. Presently, U. S. attack aircraft are identified by the prefix A-, as in A-6 Intruder, however, until the end of World War II the A- designation was shared between attack planes and light bombers for the Army aircraft. The US Navy used a separate system and at the time preferred to call similar aircraft scout bombers or torpedo bombers. For example, Douglas SBD Dauntless scout bomber was designated A-24 when used by the USAAF. It was not until 1946, when the US Navy and US Marine Corps started using the attack designation, as with many aircraft classifications, the definition of attack aircraft is somewhat vague and has tended to change over time. Current U. S. military doctrine defines it as an aircraft which most likely performs an attack mission, Attack mission means, in turn, specifically tactical air-to-ground action—in other words, neither air-to-air action nor strategic bombing is considered an attack mission. In United States Navy vocabulary, the designation for the same activity is a strike mission. Attack missions are divided into two categories, air interdiction and close air support. In the last several decades, the rise of the ubiquitous multi-role fighter has created confusion about the difference between attack and fighter aircraft. According to the current U. S. designation system, an aircraft is designed primarily for air-to-surface

7.
World War I
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World War I, also known as the First World War, the Great War, or the War to End All Wars, was a global war originating in Europe that lasted from 28 July 1914 to 11 November 1918. More than 70 million military personnel, including 60 million Europeans, were mobilised in one of the largest wars in history and it was one of the deadliest conflicts in history, and paved the way for major political changes, including revolutions in many of the nations involved. The war drew in all the worlds great powers, assembled in two opposing alliances, the Allies versus the Central Powers of Germany and Austria-Hungary. These alliances were reorganised and expanded as more nations entered the war, Italy, Japan, the trigger for the war was the assassination of Archduke Franz Ferdinand of Austria, heir to the throne of Austria-Hungary, by Yugoslav nationalist Gavrilo Princip in Sarajevo on 28 June 1914. This set off a crisis when Austria-Hungary delivered an ultimatum to the Kingdom of Serbia. Within weeks, the powers were at war and the conflict soon spread around the world. On 25 July Russia began mobilisation and on 28 July, the Austro-Hungarians declared war on Serbia, Germany presented an ultimatum to Russia to demobilise, and when this was refused, declared war on Russia on 1 August. Germany then invaded neutral Belgium and Luxembourg before moving towards France, after the German march on Paris was halted, what became known as the Western Front settled into a battle of attrition, with a trench line that changed little until 1917. On the Eastern Front, the Russian army was successful against the Austro-Hungarians, in November 1914, the Ottoman Empire joined the Central Powers, opening fronts in the Caucasus, Mesopotamia and the Sinai. In 1915, Italy joined the Allies and Bulgaria joined the Central Powers, Romania joined the Allies in 1916, after a stunning German offensive along the Western Front in the spring of 1918, the Allies rallied and drove back the Germans in a series of successful offensives. By the end of the war or soon after, the German Empire, Russian Empire, Austro-Hungarian Empire, national borders were redrawn, with several independent nations restored or created, and Germanys colonies were parceled out among the victors. During the Paris Peace Conference of 1919, the Big Four imposed their terms in a series of treaties, the League of Nations was formed with the aim of preventing any repetition of such a conflict. This effort failed, and economic depression, renewed nationalism, weakened successor states, and feelings of humiliation eventually contributed to World War II. From the time of its start until the approach of World War II, at the time, it was also sometimes called the war to end war or the war to end all wars due to its then-unparalleled scale and devastation. In Canada, Macleans magazine in October 1914 wrote, Some wars name themselves, during the interwar period, the war was most often called the World War and the Great War in English-speaking countries. Will become the first world war in the sense of the word. These began in 1815, with the Holy Alliance between Prussia, Russia, and Austria, when Germany was united in 1871, Prussia became part of the new German nation. Soon after, in October 1873, German Chancellor Otto von Bismarck negotiated the League of the Three Emperors between the monarchs of Austria-Hungary, Russia and Germany

8.
Royal Flying Corps
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The Royal Flying Corps was the air arm of the British Army before and during the First World War, until it merged with the Royal Naval Air Service on 1 April 1918 to form the Royal Air Force. During the early part of the war, the RFC supported the British Army by artillery co-operation, at the start of World War I the RFC, commanded by Brigadier-General Sir David Henderson, consisted of five squadrons – one observation balloon squadron and four aeroplane squadrons. These were first used for spotting on 13 September 1914. Aerial photography was attempted during 1914, but again only became effective the next year, by 1918, photographic images could be taken from 15,000 feet and were interpreted by over 3,000 personnel. By this time parachutes had been used by balloonists for three years, on 17 August 1917, South African General Jan Smuts presented a report to the War Council on the future of air power. On 1 April 1918, the RFC and the RNAS were amalgamated to form a new service, after starting in 1914 with some 2,073 personnel, by the start of 1919 the RAF had 4,000 combat aircraft and 114,000 personnel in some 150 squadrons. The recommendations of the committee were accepted and on 13 April 1912 King George V signed a royal warrant establishing the Royal Flying Corps, the Air Battalion of the Royal Engineers became the Military Wing of the Royal Flying Corps a month later on 13 May. The Flying Corps initial allowed strength was 133 officers, and by the end of year it had 12 manned balloons and 36 aeroplanes. The RFC originally came under the responsibility of Brigadier-General Henderson, the Director of Military Training, and had branches for the Army. Major Sykes commanded the Military Wing and Commander C R Samson commanded the Naval Wing, the RFCs motto was Per ardua ad astra. This remains the motto of the Royal Air Force and other Commonwealth air forces, the RFCs first fatal crash was on 5 July 1912 near Stonehenge on Salisbury Plain. Loraine and his observer, Staff Sergeant R. H. V, an order was issued after the crash stating Flying will continue this evening as usual, thus beginning a tradition. Four months later on 11 December 1912 Parke was killed when the Handley Page monoplane in which he was flying from Hendon to Oxford crashed. The Naval Wing, with pilots and aircraft than the Military Wing. In November 1914 the Royal Flying Corps, even taking the loss of the Naval Wing into account, had expanded sufficiently to warrant the creation of wings consisting of two or more squadrons and these wings were commanded by lieutenant-colonels. In October 1915 the Royal Flying Corps had undergone further expansion which justified the creation of brigades, further expansion led to the creation of divisions, with the Training Division being established in August 1917 and RFC Middle East, being raised to divisional status in December 1917. Finally, the air raids on London and the south-east of England led to the creation of the London Air Defence Area in August 1917 under the command of Ashmore who was promoted to major-general. Two of the first three RFC squadrons were formed from the Air Battalion of the Royal Engineers, No.1 Company becoming No.1 Squadron, RFC, a second heavier-than-air squadron, No.2 Squadron, RFC, was also formed on the same day

9.
Royal Air Force
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The Royal Air Force is the United Kingdoms aerial warfare force. Formed towards the end of the First World War on 1 April 1918, following victory over the Central Powers in 1918 the RAF emerged as, at the time, the largest air force in the world. The RAF describe its mission statement as, an agile, adaptable and capable Air Force that, person for person, is second to none, and that makes a decisive air power contribution in support of the UK Defence Mission. The mission statement is supported by the RAFs definition of air power, Air power is defined as the ability to project power from the air and space to influence the behaviour of people or the course of events. Today the Royal Air Force maintains a fleet of various types of aircraft. The majority of the RAFs rotary-wing aircraft form part of the tri-service Joint Helicopter Command in support of ground forces, most of the RAFs aircraft and personnel are based in the UK, with many others serving on operations or at long-established overseas bases. It was founded on 1 April 1918, with headquarters located in the former Hotel Cecil, during the First World War, by the amalgamation of the Royal Flying Corps, at that time it was the largest air force in the world. The RAFs naval aviation branch, the Fleet Air Arm, was founded in 1924, the RAF developed the doctrine of strategic bombing which led to the construction of long-range bombers and became its main bombing strategy in the Second World War. The RAF underwent rapid expansion prior to and during the Second World War, under the British Commonwealth Air Training Plan of December 1939, the air forces of British Commonwealth countries trained and formed Article XV squadrons for service with RAF formations. Many individual personnel from countries, and exiles from occupied Europe. By the end of the war the Royal Canadian Air Force had contributed more than 30 squadrons to serve in RAF formations, additionally, the Royal Australian Air Force represented around nine percent of all RAF personnel who served in the European and Mediterranean theatres. In the Battle of Britain in 1940, the RAF defended the skies over Britain against the numerically superior German Luftwaffe, the largest RAF effort during the war was the strategic bombing campaign against Germany by Bomber Command. Following victory in the Second World War, the RAF underwent significant re-organisation, during the early stages of the Cold War, one of the first major operations undertaken by the Royal Air Force was in 1948 and the Berlin Airlift, codenamed Operation Plainfire. Before Britain developed its own nuclear weapons the RAF was provided with American nuclear weapons under Project E and these were initially armed with nuclear gravity bombs, later being equipped with the Blue Steel missile. Following the development of the Royal Navys Polaris submarines, the nuclear deterrent passed to the navys submarines on 30 June 1969. With the introduction of Polaris, the RAFs strategic nuclear role was reduced to a tactical one and this tactical role was continued by the V bombers into the 1980s and until 1998 by Tornado GR1s. For much of the Cold War the primary role of the RAF was the defence of Western Europe against potential attack by the Soviet Union, with many squadrons based in West Germany. With the decline of the British Empire, global operations were scaled back, despite this, the RAF fought in many battles in the Cold War period

10.
United States Army
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The United States Armed Forces are the federal armed forces of the United States. They consist of the Army, Marine Corps, Navy, Air Force, from the time of its inception, the military played a decisive role in the history of the United States. A sense of unity and identity was forged as a result of victory in the First Barbary War. Even so, the Founders were suspicious of a permanent military force and it played an important role in the American Civil War, where leading generals on both sides were picked from members of the United States military. Not until the outbreak of World War II did a standing army become officially established. The National Security Act of 1947, adopted following World War II and during the Cold Wars onset, the U. S. military is one of the largest militaries in terms of number of personnel. It draws its personnel from a pool of paid volunteers. As of 2016, the United States spends about $580.3 billion annually to fund its military forces, put together, the United States constitutes roughly 40 percent of the worlds military expenditures. For the period 2010–14, the Stockholm International Peace Research Institute found that the United States was the worlds largest exporter of major arms, the United States was also the worlds eighth largest importer of major weapons for the same period. The history of the U. S. military dates to 1775 and these forces demobilized in 1784 after the Treaty of Paris ended the War for Independence. All three services trace their origins to the founding of the Continental Army, the Continental Navy, the United States President is the U. S. militarys commander-in-chief. Rising tensions at various times with Britain and France and the ensuing Quasi-War and War of 1812 quickened the development of the U. S. Navy, the reserve branches formed a military strategic reserve during the Cold War, to be called into service in case of war. Time magazines Mark Thompson has suggested that with the War on Terror, Command over the armed forces is established in the United States Constitution. The sole power of command is vested in the President by Article II as Commander-in-Chief, the Constitution also allows for the creation of executive Departments headed principal officers whose opinion the President can require. This allowance in the Constitution formed the basis for creation of the Department of Defense in 1947 by the National Security Act, the Defense Department is headed by the Secretary of Defense, who is a civilian and member of the Cabinet. The Defense Secretary is second in the chain of command, just below the President. Together, the President and the Secretary of Defense comprise the National Command Authority, to coordinate military strategy with political affairs, the President has a National Security Council headed by the National Security Advisor. The collective body has only power to the President

11.
Lockheed Martin F-35 Lightning II
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The Lockheed Martin F-35 Lightning II is a family of single-seat, single-engine, all-weather stealth multirole fighters. The fifth-generation combat aircraft is designed to perform ground attack and air defense missions, on 31 July 2015, the United States Marines declared ready for deployment the first squadron of F-35B fighters after intensive testing. On 2 August 2016, the U. S. Air Force declared its first squadron of F-35A fighters combat-ready, the F-35 descends from the X-35, the winning design of the Joint Strike Fighter program. An aerospace industry led by Lockheed Martin designed and manufactures it. Other major F-35 industry partners include Northrop Grumman, Pratt & Whitney, the F-35 first flew on 15 December 2006. The United States plans to buy 2,457 aircraft and its variants are to provide the bulk of the crewed tactical airpower of the U. S. Air Force, Navy and the Marine Corps over the coming decades. Deliveries of the F-35 for the U. S. military are scheduled until 2037 with a service life up to 2070. The United States principally funds the F-35 JSF development, with funding from partners. The partner nations are either NATO members or close U. S. allies, the program is the most expensive military weapons system in history, and has been much criticized inside and outside government, in the U. S. and in allied countries. By 2014, the program was $163 billion over seven years behind schedule. Critics also contend that the programs high sunk costs and political momentum make it too big to kill, the JSF program was designed to replace the United States military F-16, A-10, F/A-18 and AV-8B tactical fighter and attack aircraft. To keep development, production, and operating costs down, a design was planned in three variants that share 80 percent of their parts, F-35A, conventional take off and landing variant. F-35B, short-take off and vertical-landing variant, the design goals call for the F-35 to be the premier strike aircraft through 2040 and to be second only to the F-22 Raptor in air supremacy. Although both aircraft met or exceeded requirements, the X-35 design was considered to have less risk, the designation of the new fighter as F-35 is out-of-sequence with standard DoD aircraft numbering, by which it should have been F-24. It came as an even to the company, which had been referring to the aircraft in-house by this expected designation. Instead F-16s have been used as trainers between the T-38 and the F-35. The T-X was intended to be used to train future F-35 pilots, based on wind tunnel testing, Lockheed Martin slightly enlarged its X-35 design into the F-35. The forward fuselage is 5 inches longer to make room for avionics, correspondingly, the horizontal stabilators were moved 2 inches rearward to retain balance and control

12.
Curtiss P-40 Warhawk
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The Curtiss P-40 Warhawk is an American single-engined, single-seat, all-metal fighter and ground-attack aircraft that first flew in 1938. The P-40 design was a modification of the previous Curtiss P-36 Hawk which reduced development time and enabled a rapid entry into production, the Warhawk was used by most Allied powers during World War II, and remained in frontline service until the end of the war. P-40 Warhawk was the name the United States Army Air Corps and after June 1941, USAAF-adopted name for all models, making it the official name in the U. S. for all P-40s. The British Commonwealth and Soviet air forces used the name Tomahawk for models equivalent to the P-40B and P-40C, P-40s first saw combat with the British Commonwealth squadrons of the Desert Air Force in the Middle East and North African campaigns, during June 1941. However, between 1941 and 1944, the P-40 played a role with Allied air forces in three major theaters, North Africa, the Southwest Pacific, and China. It also had a significant role in the Middle East, Southeast Asia, Eastern Europe, Alaska, the P-40s performance at high altitudes was not as important in those theaters, where it served as an air superiority fighter, bomber escort and fighter-bomber. The P-40 offered the advantage of low cost, which kept it in production as a ground-attack aircraft long after it was obsolete as a fighter. On 14 October 1938, Curtiss test pilot Edward Elliott flew the prototype XP-40 on its first flight in Buffalo, the first prototype placed the glycol coolant radiator in an underbelly position on the fighter, just aft of the wings trailing edge. USAAC Fighter Projects Officer Lieutenant Benjamin S. Kelsey flew this prototype some 300 miles in 57 minutes, hiding his disappointment, he told reporters that future versions would likely go 100 miles per hour faster. Kelsey was interested in the Allison engine because it was sturdy and dependable, Curtiss engineers worked to improve the XP-40s speed by moving the radiator forward in steps. Seeing little gain, Kelsey ordered the aircraft to be evaluated in a NACA wind tunnel to identify solutions for better aerodynamic qualities, from 28 March to 11 April 1939, the prototype was studied by NACA. Based on the data obtained, Curtiss moved the glycol coolant radiator forward to the chin, other improvements to the landing gear doors and the exhaust manifold combined to give performance that was satisfactory to the USAAC. Without beneficial tail winds, Kelsey flew the XP-40 from Wright Field back to Curtisss plant in Buffalo at an speed of 354 mph. Further tests in December 1939 proved the fighter could reach 366 mph, an unusual production feature was a special truck rig to speed delivery at the main Curtiss plant in Buffalo, New York. The rig moved the newly built P-40s in two components, the main wing and the fuselage, the eight miles from the plant to the airport where the two units were mated for flight and delivery. The P-40 was conceived as an aircraft and was agile at low and medium altitudes. At medium and high speeds it was one of the tightest-turning early monoplane designs of the war, and it could out turn most opponents it faced in North Africa and the Russian Front. In the Pacific Theater it was out-turned at lower speeds by the lightweight fighters A6M Zero, the American Volunteer Group Commander Claire Chennault advised against prolonged dog-fighting with the Japanese fighters due to speed reduction favouring the Japanese